package com.hmdp.utils;

import cn.hutool.core.lang.UUID;
import org.springframework.core.io.ClassPathResource;
import org.springframework.core.io.Resource;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.data.redis.core.script.RedisScript;

import java.util.Collections;
import java.util.concurrent.TimeUnit;

/**
 * @author 王艺锡
 * @version 1.0
 */
public class SimpleRedisLock implements ILock{

    private String name;
    private StringRedisTemplate stringRedisTemplate;
    private static final DefaultRedisScript<Long> UNLOCK_SCRIPT;
    static {
        UNLOCK_SCRIPT = new DefaultRedisScript<>();
        UNLOCK_SCRIPT.setLocation(new ClassPathResource("unlock.lua"));
        UNLOCK_SCRIPT.setResultType(Long.class);
    }


    public SimpleRedisLock(String name, StringRedisTemplate stringRedisTemplate) {
        this.name = name;
        this.stringRedisTemplate = stringRedisTemplate;
    }

    private static final String KEY_PREFIX = "lock:";
    private static final String ID_PREFIX = UUID.randomUUID().toString(true);

    @Override
    public boolean tryLock(long timeoutSec) {
        String threadId = ID_PREFIX + "-" + Thread.currentThread().getId();
        Boolean success = stringRedisTemplate
                .opsForValue()
                .setIfAbsent(KEY_PREFIX + name, threadId, timeoutSec, TimeUnit.SECONDS);

        return Boolean.TRUE.equals(success);
    }

    @Override
    public void unlock() {
        //调用lua脚本，可以让验证锁和删除锁一起执行
        stringRedisTemplate.execute(UNLOCK_SCRIPT,
                Collections.singletonList(KEY_PREFIX + name),
                ID_PREFIX + "-" + Thread.currentThread().getId());
    }

   /* @Override
    public void unlock() {
        //获取线程标识
        String threadId = ID_PREFIX + "-" + Thread.currentThread().getId();
        //获取锁中的标识
        String id = stringRedisTemplate.opsForValue().get(KEY_PREFIX + name);

        if(threadId.equals(id)) {
            stringRedisTemplate.delete(KEY_PREFIX + name);
        }
    }*/
}
